disappearance, jenna. jon: new dna testing finds widespread fraud with regard to fish. it is bait and switch. and consumers are on the hook. what is going on? >> reporter: this is one way to know what you're getting. but it's no way to fight seafood fraud. 55% of consumers in los angeles, 48% in boston paid for one fish and got another. for instance, can you tell the difference between a snapper, red snapper and a cheaper talapia? a sole and a sea bass, a wild salmon and a steelhead trout, $20 a pound. probably not. many retailers are banking on